(Know-Nothing)(US historical)a member of a political party in the US, prominent from 1853 to 1856, which was antagonistic towards Roman Catholics and recent immigrants, and whose members preserved its secrecy by denying its existence (美 史)一无所知党成员(美国1853–1856年强烈反对罗马天主教和新移民的政党成员,他们严守秘密,否认其组织的存在)